Specifications

SMSM receives fault information from the SMIM. When a fault condition
is sensed, the system microprocessor informs the host CPU of this fault
by way of the RS-232 interface.
2.4.5 Shuttle Matrix Imaging Microprocessor (SMIM)
The SMIM is located in the card cage on the right side of the printer. It
sends commands to the SMIH board for dot imaging. That is, it builds
the dot rows for font characters or graphic displays. The SMIM board
also controls the ribbon and shuttle motors and paper movement. It also
interfaces to the paper motion detector, cover interlock switch, paper out
switch, and striker bar open switch.
2.4.6 Shuttle Matrix Image Hardware (SMIH)
The SMIH is located in the card cage on the right side of the printer.
This board is directly concerned with laying down an image of a single
horizontal line of dots. It receives serial data from the SMIM boards in
bursts of 33 bits for printing. It sends command signals to the SHAD
board, to enable printing, one bit for each actuator in the print modules.
2.4.7 Shuttle Head Actuator Driver (SHAD)
The SHAD board is vertically mounted in the top rear of the printer.
It receives dot image information in serial form from the SMIH board,
converts it to parallel form, and drives the appropriate print head
actuators.
The SHAD board contains 33 actuator drivers.
The SHAD also contains the Actuator Test circuit. This is activated each
time the printer is turned ON. It checks for open circuit print actuator
coils.
If the printer actuator assembly temperature exceeds a factory set level,
a circuit in the SHAD reduces the printing rate by enabling printing on
every seventh shuttle swing.
THEORY OF OPERATION 2–11